package unionfind;

public class UnionFind1 implements UF {

    private int[] id;

    public UnionFind1(int size){
        id = new int[size];
        for (int i = 0; i < id.length; i++) {
            id[i] = i;
        }
    }

    @Override
    public int getSize() {
        return id.length;
    }

    private int find(int p){
        if (p < 0 && p >= id.length){
            throw new IllegalArgumentException("p is out of bound");
        }
        return id[p];
    }
    // 查询元素p和元素q是否所属一个集合
    @Override
    public boolean isConnected(int p, int q) {
        return find(p) == find(q);
    }

    // 合并元素p和元素q所属的集合
    @Override
    public void unionElements(int p, int q) {
        int pID = find(p);
        int qID = find(q);
        if(pID == qID){
            return;
        }

        for (int i = 0; i < id.length; i++) {
            if (id[i] == pID){
                id[i] = qID;
            }
        }
    }


}
